Former SA minister to hang on in Mawson

A former Labor minister looks likely to hang on to his Adelaide seat as the counting of votes draws to a close in the South Australian election.

Leon Bignell, the former tourism minister, leads Liberal challenger Andy Gilfillan by just a single vote on the primary count in Mawson. However, he has a 110-vote buffer on a two-party basis with more than 90 per cent of ballots counted.

Today was the last day for postal votes to be received with the Electoral Commission to officially start declaring results in the 47 lower house seats from Monday.

With Mr Bignell hanging on, Labor will finish with 19 seats, the new Liberal government will have 25, and there will be three independents.

Leon Bignell earlier this month. (AAP) (AAP)

The former minister has described the drawn-out count in Mawson as "excruciating" but said all everyone could do was wait for the result to be determined.

His likely victory has defied the odds after boundary changes made his seat notionally Liberal.